1. Field of the Invention
The present invention relates to fluid exchange devices for replacing used fluid with a fresh fluid in a fluid circuit, and more particularly to an apparatus and method of use for achieving a fluid exchange of a fluid circulation circuit such as a vehicular automatic transmission, a vehicular power steering system, a vehicular engine oil system, or a vehicular cooling system.
2. Related Background Art
Various devices have been utilized to achieve fluid exchanges for vehicular automatic transmissions. Applicant's U.S. Pat. Nos. 6,378,657; 6,330,934; 6,267,160; 6,223,79; 6,164,346; 6,105,635; 6,082,416; RE36,65; 5,964,278; and 5,318,080 disclose devices, systems, or methods for performing a fluid exchange. Each of these patents are incorporated by reference herein in their entireties. The prior art also includes various externally powered exchange devices wherein the power to effect an exchange procedure is at least in part provided by an electric pump. Some of these externally powered devices utilize a vehicle's electric system for activation. One unresolved problem has been the need for a fluid exchange system which requires no external power source such as an electric motor or compressed air.
A need also exists for a device for servicing vehicular automatic transmissions having the following characteristics: one which requires no external powering source other than the fluid pressure from the accessed fluid circulation circuit; a reciprocating pump having a pump volume which is a fraction of the fluid volume necessary for the fluid exchange; an onboard fresh fluid supply tank reservoir of a capacity sufficient to perform a fluid exchange for most vehicle automatic transmissions; and a pump matching rates of flow and volumes exchanged during the and exchange procedure.
U.S. Pat. No. 6,223,790 discloses a system able to operate without electrical or compressed air power in its 1st and 5th embodiments, both embodiments being reciprocating fluid exchangers, and both of which employ a mechanically actuated spring and detent operated fluid control valve.
The need remains for such a self powered, fluid flow rate and volume equalized, fluid exchange system where any necessary fluid control valving is provided by an alternative mechanism which does not employ spring and detent, such as disclosed in the first and fifth embodiments of U.S. Pat. No. 6,223,790.
A fluid exchange unit for automatic transmissions, power steering and cooling systems which does not require connection to a vehicle's electric system would be desired. In addition, such a unit can be very portable and useful away from a service station given that no external power supply is required to operate the exchange device This portability is viewed as advantageous and desired by service technicians.